Fed Up!!!

Sorry to rant, but I've been battling problem after problem with this motorbike project, having left me stranded five times so far, ranging from two to 13 miles away... The final straw was this last stranding, 13 miles from home, on a now very heavy bike with much chain friction...and of course, all uphill home, because I suddenly lost spark. I know because I stuck a screwdriver into the plug wire and grabbed it with my bare hands while the engine was spinning. Five strandings in a row merely trying to get to work and back (20 miles each way) just plain bites.

So I've "killed" the kill switch, checked the magneto solder joints, made sure the "white wire" nor any others were grounded out. Connections all redone...still no spark. Only thing I haven't done, which I just thought of, is to see if magneto actually spins with motor turning.

If I were to use a multi-meter on the magneto outputs, what should
I see? High voltage DC? or AC? Low votage? Anybody want my whole kit I'm about to remove for good and never return to motorbiking?

UncleKudzu said:

ackkk! stop it, you're scaring me! i'm not really much of a mechanic and now i've invested my hard-gotten into this crazy motorized bike idea.

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Scary thing is...i AM professional car mechanic, and the 40-odd carb adjustments trying to merely get the mixture dialed in, much less the multiple string of mechanical issues....I'm second...no, triple guessing this whole thing.

Easy Rider said:

Usually on my old bike the connectors would disconnect the wires and I would have any spark. I wasn't sure what you meant by killing the kill switch but did you check with an ohm meter to see if the switch isn't grounding out? If that fails, I think its time for a new plug and coil.

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"killed the kill switch" meaning on the side of the highway I pulled apart all the wiring and bypassed the kill switch by biting off the insuluation and tightly twisting and taping the mag/coil wires together, ensuring no oil or goop or grounds jumping the circuits, and physically touching the spark output terminal without getting shocked.

I have a large box filled with known good Ford Lincoln Mercury parts that I've purchased and scrounged for, and daily use for diagnosis. However, I have no such parts for motorbikes, such as trying out a new CDI which I can't even locae online... and thus have to rely on actual testing.... Such as the actual output of the mag. If I had specific reading to look for, I could condemn one part versus another.

Maybe this is payback for the times when I've had a customer's car that defied all logic, and I have say that I'm literally guessing at a cause and that the customer is going to have to pay for the process of elimination?

I've been suddenly accustomed to the public transit sytem. It's kind of nice, despite the three mile from home, one mile from work distance. But my infinitely lighter pedal bike on the bus's bike rack after waiting 45 minutes to arrive, is better than the HOPE of motoring all the way.

Back to topic, mulimeter reading for no spark? Does the Magneto send out a somewhat high positive voltage that the CDI stores/amplifies/disperses?

Well, I ohm checked evrything today, double checking the meter leads together for baseline check of half ohm within the meter and leads.

Magneto has black, blue, and white wires. White for lights etc, black and blue connect to CDI black and blue wires. Mag black to blue ohms=open circuit. CDI black to blue ohms=open circuit. CDI black to spark plug output 7300 ohms (output half of "transformer-like coil" present, but input half dead?). All wires to ground/frame/engine are open, so nothing shorted.

I guess they both fried together, sort of a Romeo and Juliet ending I guess?
I'm not even going to bother fixing it. I've gotten a free 1978 Motobecane pedal start moped just before the motorbike died, and main issues are nearly repaired, should be rideable soon.......only thing is, this forum is SO MUCH BETTER than the moped forums!